Macaque multimeric soluble CD40 ligand and GITR ligand constructs are immunostimulatory molecules in vitro

Area of Science:

• Immunology
• Vaccinology
• Molecular Biology

Background:

• CD40 ligand (CD40L) and GITR ligand (GITRL) are members of the tumor necrosis factor superfamily with potential as vaccine adjuvants.
• Previous studies in mice demonstrated that multimeric soluble CD40L enhanced CD8(+) T-cell responses more effectively than monomeric or membrane-bound forms.
• The development of similar molecular adjuvants for non-human primate studies is crucial for advancing vaccine research.

Purpose of the Study:

• To construct and evaluate multimeric soluble forms of macaque CD40L and GITRL as potential vaccine adjuvants.
• To assess the activity of these molecular adjuvants in B-cell proliferation and T-cell costimulation assays.
• To investigate the ability of macaque GITRL to overcome the immunosuppressive effects of regulatory T cells.

Main Methods:

• Construction of two-trimer and four-trimer soluble forms of macaque CD40L.
• Synthesis of a four-trimer soluble form of macaque GITRL.
• Assessment of CD40L activity in B-cell proliferation assays using macaque and human cells.
• Evaluation of GITRL's costimulatory effects on CD4(+) T-cell proliferation and its impact on regulatory T-cell function in mixed leukocyte reactions.

Main Results:

• Both two-trimer and four-trimer macaque CD40L induced B-cell proliferation in assays involving macaque and human cells.
• Four-trimer macaque GITRL demonstrated costimulatory activity for CD4(+) T-cell proliferation in human cell assays.
• Four-trimer macaque GITRL effectively abrogated the immunosuppressive effects of CD4(+) CD25(+) regulatory T cells.

Conclusions:

• Multimeric soluble CD40L and GITRL are active molecular adjuvants with potential for vaccine development.
• These novel adjuvants show efficacy in stimulating B-cell and T-cell responses and overcoming immune suppression.
• The developed molecular adjuvants offer valuable tools for preclinical vaccine studies in simian immunodeficiency virus and other macaque models.